Marketing Agency Ad Spend Billing: Merchant Account Guide

A marketing agency's invoice often hides a second, much larger business inside it. A $150,000 monthly bill might be $15,000 of real agency revenue and $135,000 of client ad spend simply passing through the agency's account. A standard fraud model sees one large recurring charge and flags it, with no way to tell pass-through spend from earned revenue.

Why agencies get flagged as high-risk#

That distinction matters enormously at underwriting, because the agency's actual risk exposure is tied to its own fee, not the media budget flowing through it. On top of that, agencies sell an intangible, judgment-based deliverable: strategy, creative, campaign management. That makes "services not as described" disputes harder to defend than a shipped-goods chargeback, especially when a client becomes unhappy with results and disputes a retainer instead of raising it with the agency directly.

Retainer billing at a fixed monthly fee adds its own friction. A client who feels a slow month didn't justify the charge will sometimes dispute it, even though the retainer structure was agreed to upfront. A sudden large new client can also trigger volume swings that a standard processor misreads as risk rather than normal growth.

How the account gets structured#

The fix starts with separating pass-through ad spend from the agency's own management-fee revenue, either through separate line items or separate MIDs, so underwriting evaluates the real exposure instead of the full invoice total. From there, a high-risk merchant account is sized for high-ticket B2B invoicing, including large recurring retainers and irregular project fees, with statement-of-work and campaign-reporting documentation tied to every billing cycle.

ACH processing is worth pairing with card acceptance for large retainer and ad-spend invoices, since it meaningfully reduces per-transaction cost on high-ticket B2B billing. Your pricing model matters here too, because interchange plus versus flat rate changes what a six-figure invoice actually costs you to accept.

Why pass-through billing looks like third-party processing#

There's a specific reason underwriters get cautious about pass-through billing, and it isn't the size of the number. Money moving through your account on behalf of someone else looks structurally like third-party payment processing, and that's a category federal bank regulators single out for extra scrutiny.

The FDIC's guidance on payment processor relationships, revised February 3, 2026, says managing this risk "poses an increased challenge for the financial institution when there may not be a direct customer relationship with the merchant," and that agreements should provide for immediate account closure and adequate reserve requirements to cover anticipated chargebacks (FDIC).

Worth being precise about how far that goes. The guidance reserves its strongest language for nested processors and aggregator relationships, where it says risk to the institution is "significantly elevated" because those arrangements are extremely difficult to monitor and control. An agency billing pass-through ad spend isn't a nested processor, so that sentence isn't about you. The increased-challenge language is.

An agency isn't a payment processor and shouldn't be treated as one. But if your application shows $150,000 a month in volume against $15,000 of revenue on your financials, the underwriter has to work out what the other $135,000 is. Answering that before they ask it, with a clean split between fee and float, is the difference between a straightforward approval and a file that sits in review.

The separation keeps mattering after approval too. Reserve percentages, volume caps, and monthly limits all get set against whatever number the underwriter believes is yours. Set against gross billings, a rolling reserve on a pass-through account can hold back more than the agency actually earned that month. We covered the mechanics in what a rolling reserve is.

What a typical management fee actually looks like#

Fee structures vary, but the range quoted across the industry sits at roughly 10 to 20% of managed ad spend, with the percentage usually falling as budgets grow. One caveat we'd rather state than hide: that's a widely repeated range rather than a figure any trade body publishes, so treat it as orientation and not as a benchmark you can cite at anyone.

Run the arithmetic and the underwriting problem becomes obvious. A $150,000 monthly client invoice at a 10% fee nets the agency $15,000 in real revenue, with $135,000 moving through on its way to the ad platforms. At 15% it's roughly $22,500 earned against $127,500 pass-through. The shape doesn't change at any fee level: a small real number hiding inside a much larger total.

Some agencies sidestep the problem entirely by having clients pay the ad platforms directly and billing only for the fee. That's much cleaner for underwriting, and it's worth considering if your account keeps hitting limits. It costs you the float and some client convenience, so it's a genuine trade rather than an obvious win.

Defending a results-based dispute#

Retainer agreements should state clearly that the fee covers agreed work, not guaranteed outcomes. Campaign performance depends on factors outside the agency's control, including platform algorithm changes. Monthly reporting, deliverable logs, and the signed statement of work are the documentation card networks look for in a services-not-rendered dispute, and it helps to know how a dispute differs from a refund before you respond to one. Ethoca and Verifi alert integration lets a dispute get addressed directly with the client before it becomes a formal chargeback.